JP5734795B2 - Biotreatment method for biomass - Google Patents

Description

  The present invention relates to a biomass pretreatment method.

  In recent years, it has been studied to use a gasoline-ethanol mixed fuel as a fuel for automobiles. When bioethanol obtained by fermentation and distillation of plant substances is used as the ethanol, a so-called carbon neutral effect can be obtained by strict soil management, reducing carbon dioxide emissions and global warming. It is thought that it can contribute to prevention of

  However, when a crop such as sugar cane or corn is used as the plant substance, there is a problem that the supply amount as food or feed decreases because the crop is consumed in large quantities as a raw material for ethanol. Then, the technique which manufactures ethanol using the lignocellulosic biomass which does not become food or feed as said plant substance is examined.

  The lignocellulosic biomass contains cellulose, and it can be decomposed into glucose by subjecting the cellulose to saccharification treatment using a saccharifying enzyme, and the obtained glucose can be fermented to obtain ethanol.

  However, the lignocellulosic biomass mainly contains hemicellulose and lignin in addition to cellulose, and usually the cellulose and the hemicellulose are firmly bound to the lignin. It is difficult to carry out the reaction. Therefore, when enzymatically saccharifying the cellulose, it is desirable that the lignocellulosic biomass is pretreated in advance so that the enzymatic saccharification reaction is possible.

  In order to make the lignocellulosic biomass ready for an enzymatic saccharification reaction, a pretreatment for mixing the lignocellulosic biomass as a substrate with ammonia water to form a substrate mixture and holding the substrate mixture at a predetermined temperature for a predetermined time The method is known. According to the pretreatment method, lignin is dissociated from the substrate or the substrate is swollen, whereby the lignocellulosic biomass as the substrate can be brought into a state capable of enzymatic saccharification reaction.

  In addition, in this application, dissociation means cut | disconnecting at least one part coupling | bonding among the binding sites of lignin couple | bonded with cellulose etc. Swelling means that voids are formed in cellulose or the like constituting crystalline cellulose by the ingress of liquid, or the voids are generated inside the cellulose fibers to expand.

  Further, the ammonia water can be recovered by cooling and condensing gaseous ammonia separated from the substrate mixture after the pretreatment and dissolving it in water.

  Therefore, in the pretreatment method, a second heat medium is supplied to a heat pump that heats the first heat medium that heats the substrate mixture, and the second heat medium is heated between the first heat medium and the heat medium. A method has been proposed in which the ammonia is cooled by replacement, and the ammonia is cooled using the cooled second heat medium (see, for example, Patent Document 1).

JP 2010-142680 A

  However, when the conventional pretreatment method is performed in a batch system, immediately after the pretreatment of the substrate mixture is completed, the ammonia released and separated from the ammonia-containing saccharification pretreatment product has a high concentration and a large amount. Become. As a result, a large amount of cooling heat energy is required for cooling the high concentration and large amount of ammonia, and it is difficult to quickly cool with a high temperature and a small amount of heat medium when starting the heat pump.

  In order to solve the inconvenience, it is conceivable to increase the size of the heat pump itself or to provide other cooling means, but when doing so, an increase in equipment cost is inevitable. In addition, if the time immediately after the end of the pretreatment is over, the concentration and generation amount of ammonia will decrease, and the cooling heat energy required for cooling will also decrease. There is also the inconvenience of doing.

  The present invention eliminates such inconveniences, and immediately and efficiently cools a high concentration and a large amount of ammonia released from the ammonia-containing saccharification pretreatment immediately after the pretreatment of the substrate mixture is completed. It aims at providing the pre-processing method of the biomass which can be processed.

In order to achieve this object, the present invention comprises a step of mixing a lignocellulosic biomass and ammonia water as a substrate in a batch system to obtain a substrate mixture, heating the substrate mixture to a predetermined temperature, and For a predetermined period of time to dissociate lignin from the substrate or swell the substrate to obtain an ammonia-containing saccharification pretreatment product, and to release ammonia from the ammonia-containing saccharification pretreatment product to separate ammonia. A process for obtaining a pre-treated ammonia separation saccharification product, and a step of cooling and condensing the ammonia released from the ammonia-containing saccharification pre-treatment product and dissolving it in water and recovering it as ammonia water. A second heat medium is supplied to a heat pump that heats the first heat medium to be heated, and the second heat medium is interposed between the first heat medium and the heat pump. In the biomass pretreatment method in which the ammonia is cooled using the cooled second heat medium and cooled by using the second heat medium that is cooled, the second heat medium is circulated between the heat pump and the portion that cools the ammonia. A bypass circulation path is provided in the path to circulate to the heat pump while avoiding the portion that cools the ammonia, and the second heat medium is circulated through the bypass circulation path so that the second heat medium is passed to the circulation path. A predetermined amount of the second heat medium cooled to a temperature lower than the temperature at the time of circulation and cooled to a temperature lower than the temperature at the time of circulation to the circulation path is stored in advance, and the ammonia-containing saccharification pretreatment product between the early stage dissipation of ammonia, to a concentration of ammonia dissipated it is reduced to a predetermined concentration, and the amount of the ammonia is reduced to a predetermined amount, savings Characterized by cooling the ammonia by the second heat medium being.

  The pretreatment method of the present invention is a batch type, and first, lignocellulosic biomass as a substrate and aqueous ammonia are mixed to obtain a substrate mixture.

  Next, by holding the substrate mixture at a predetermined temperature for a predetermined time, lignin is dissociated from the substrate or the substrate is swollen to obtain an ammonia-containing saccharification pretreatment product. The ammonia-containing saccharification pretreatment product is pretreated so that the lignocellulosic biomass as the substrate can undergo an enzymatic saccharification reaction, but has a high pH because it contains ammonia. It cannot be served.

  Therefore, next, ammonia is diffused and separated from the ammonia-containing saccharification pretreatment product, while the diffused ammonia is cooled and condensed and dissolved in water to be recovered as ammonia water. As a result, an ammonia separation pretreatment product from which ammonia has been separated can be obtained, and the ammonia separation pretreatment product can be subjected to an enzymatic saccharification reaction.

  The cooling of the ammonia is performed by supplying a second heat medium to a heat pump that heats the first heat medium that heats the substrate mixture and exchanging heat between the second heat medium and the first heat medium. This is performed by using the cooled second heat medium. By the way, since the pretreatment method of the present invention is a batch type, immediately after the pretreatment of the substrate mixture, a large amount of ammonia is released from the ammonia-containing saccharification pretreatment product, and the ammonia is cooled. In order to do so, a large amount of cooling heat energy is required.

  Therefore, in the pretreatment method of the present invention, a bypass for circulating the second heat medium to the heat pump while avoiding the portion for cooling the ammonia in a circulation path for circulating the second heat medium to the portion for cooling the heat pump and the ammonia. A circulation path is provided, and the second heat medium is circulated through the bypass circulation path. In this case, the second heat medium is gradually cooled to a lower temperature because the cooling heat energy is not lost by the cooling of the ammonia.

Therefore, as described above, the second heat medium is cooled to a temperature lower than the temperature at which the second heat medium is circulated through the circulation path, and is cooled to a temperature lower than the temperature at which the second heat medium is circulated through the circulation path. A predetermined amount of heat medium is stored in advance. Then, during the period from the initial stage of the dissipation of ammonia the ammonia-containing saccharification pretreated product, to a concentration of ammonia dissipated it is reduced to a predetermined concentration, and the amount of the ammonia is reduced to a predetermined amount, the reservoir The ammonia is cooled by the second heat medium.

  According to the pretreatment method of the present invention, in this way, the concentration of ammonia released from the ammonia-containing saccharification pretreatment product is reduced to a predetermined concentration, and the amount of ammonia is reduced to a predetermined amount. Can be quickly and efficiently performed at low cost without providing other cooling means or increasing the size of the heat pump itself.

  In the pretreatment method of the present invention, the heat pump may use a single heat medium, but by using a binary heat pump including two kinds of heat medium, the cooling of the ammonia is more efficient. Can be done well.

  In the pretreatment method of the present invention, the storage of the second heat medium is preferably performed between the step of obtaining the substrate mixture and the step of obtaining the ammonia-containing saccharification pretreatment product. Since the pretreatment method of the present invention is a batch system, the ammonia is not cooled during the step of obtaining the substrate mixture and the step of obtaining the ammonia-containing saccharification pretreatment product. Accordingly, the second heat medium can be efficiently stored by operating the heat pump during the step of obtaining the substrate mixture.

The system block diagram which shows the apparatus structure which implements the pre-processing method of this embodiment. Explanatory drawing which shows schematically an example of the line of the binary system heat pump shown in FIG.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

  The pretreatment method of this embodiment can be implemented using the pretreatment apparatus 1 shown in FIG.

  The pretreatment device 1 includes a reaction vessel 2, an ammonia condenser 3, an ammonia absorption tower 4, and an ammonia tank 5.

  The reaction vessel 2 is provided with a substrate supply conduit 6 and an ammonia water supply conduit 7 at the top, and a first exhaust conduit 8 for discharging ammonia gas and guiding it to the ammonia condenser 3 is connected to an exhaust valve 9. It is arranged via the bag filter 10. The substrate supply conduit 6 supplies lignocellulosic biomass as a substrate, such as rice straw, to the reaction vessel 2, and the ammonia water supply conduit 7 supplies ammonia water to the reaction vessel 2 from an ammonia water tank (not shown).

  The reaction vessel 2 also includes a motor 11 disposed at the top, a rotary shaft 12 that hangs down from the motor 11 into the reaction vessel 2, and a stirring blade 13 that extends from the rotary shaft 12 in the horizontal direction. In addition, a jacket 14 through which a heat medium is circulated is provided. A hot water conduit 15 is connected to the jacket 14.

  The hot water conduit 15 supplies hot water as a first heat medium derived from the upper part of the jacket 14 to a hot water primary tank 16, a hot water primary pump 17, an air cooling fan 18, a two-way heat pump 19, and a first switching valve 20. And is circulated to the bottom of the jacket 14.

  A warm water bypass conduit 21 is connected to the first switching valve 20, and the other end of the warm water bypass conduit 21 is connected to the warm water primary tank 16 via a second switching valve 22. A high temperature water conduit 24 is connected to the second switching valve 22, and the other end of the high temperature water conduit 24 is connected to a hot water secondary tank 25. The 1st switching valve 20 and the 2nd switching valve 22 switch the flow path of warm water according to the temperature detected by the 1st temperature sensor 23 provided in the binary system heat pump 19, respectively.

  The hot water secondary tank 25 is provided with a high temperature water supply conduit 26, and the high temperature water supply conduit 26 is connected to the hot water conduit 15 on the downstream side of the first switching valve 20 via the hot water secondary pump 27. . The hot water primary tank 16 is provided with a first make-up water conduit 28, and the first make-up water conduit 28 is connected to the first make-up water tank 30 through a first water supply valve 29.

  The ammonia condenser 3 condenses liquid ammonia by cooling at least a part of the ammonia gas introduced from the first exhaust conduit 8, and the first exhaust conduit 31 for discharging the condensed ammonia is provided. I have. The first drainage conduit 31 is connected to the ammonia tank 5 via a condensation tank 32 and a first drainage pump 33 for further cooling the condensed ammonia.

  The ammonia condenser 3 includes a second exhaust conduit 34 that discharges ammonia gas that has not been condensed and guides the ammonia gas to the ammonia tank 5. The second exhaust conduit 34 is connected to the ammonia tank 5 via an on-off valve 35. It is connected. The second exhaust conduit 34 branches from the third exhaust conduit 36 upstream of the on-off valve 35, and the third exhaust conduit 36 includes a vacuum pump 37 on the way, and joins the second exhaust conduit 34 downstream of the on-off valve 35. doing.

  The ammonia absorption tower 4 communicates with the top surface of the ammonia tank 5 at the bottom, and absorbs (dissolves) the ammonia gas guided to the ammonia tank 5 by the second exhaust conduit 34 in the ammonia water. For this reason, the ammonia absorption tower 4 is provided with a showering device 39 for showering the ammonia water supplied from the ammonia tank 5 via the ammonia water circulation conduit 38.

  The ammonia water circulation conduit 38 is connected from the ammonia tank 5 to the showering device 39 via the circulation pump 40, the ammonia water heat exchanger 41, and the ammonia concentration sensor 42. The ammonia water heat exchanger 41 has a function of cooling the ammonia water circulated through the ammonia water circulation conduit 38. The ammonia absorption tower 4 is provided with a second makeup water conduit 43, and the second makeup water conduit 43 is connected to a second makeup water tank 45 via a second water supply valve 44.

  The ammonia tank 5 includes a second drainage conduit 46 for discharging ammonia water, and the second drainage conduit 46 is connected to an ammonia water tank (not shown) via a second drainage pump 47.

  The ammonia condenser 3 is connected to a low-temperature water conduit 48 for cooling the ammonia gas introduced from the first exhaust conduit 8. The low temperature water conduit 48 converts low temperature water derived from the ammonia condenser 3 as a second heat medium into a low temperature water primary tank 49, a low temperature water primary pump 50, a two-way heat pump 19, a third switching valve 51, ammonia. The water is circulated to the ammonia condenser 3 through the water heat exchanger 41 and the condensation tank 32.

  A low temperature water bypass conduit 52 is connected to the third switching valve 51, and the other end of the low temperature water bypass conduit 52 is connected to the low temperature water primary tank 49 via the fourth switching valve 53. A cold water conduit 55 is connected to the fourth switching valve 53, and the other end of the cold water conduit 55 is connected to the low temperature water secondary tank 56. The third switching valve 51 and the fourth switching valve 53 switch the flow path of the low-temperature water according to the temperature detected by the second temperature sensor 54 provided in the binary system heat pump 19.

  The low temperature water secondary tank 56 is provided with a cold water supply conduit 57, and the cold water supply conduit 57 is connected to the low temperature water conduit 48 downstream of the third switching valve 51 via the low temperature water secondary pump 58. Yes. The low temperature water primary tank 49 is provided with a third make-up water conduit 59, and the third make-up water conduit 59 is connected to the third make-up water tank 61 through the third water supply valve 60.

  Next, the operation of the pretreatment device 1 of this embodiment will be described.

  In the pretreatment device 1, first, the ammonia separation saccharification pretreatment product obtained in the previous treatment is discharged from the discharge port (not shown) at the bottom of the reaction vessel 2 and transferred to the next step. Thereafter, lignocellulosic biomass as a new substrate such as rice straw is supplied to the reaction vessel 2 from the substrate supply conduit 6, and ammonia water is supplied to the reaction vessel 2 from the ammonia water supply conduit 7.

  At this time, in the reaction vessel 2, the rotating shaft 12 is rotationally driven by the motor 11, and the rice straw and the ammonia water are stirred by the stirring blade 13, whereby the substrate mixed solution is prepared.

  In the present embodiment, after the previous ammonia separation saccharification pretreatment product is discharged from the reaction vessel 2, a new substrate and aqueous ammonia are supplied to the reaction vessel 2 and mixed until a substrate mixture is obtained. This corresponds to the step of obtaining a substrate mixture.

  The substrate mixed solution is heated to a predetermined temperature, for example, a temperature in the range of 80 to 85 ° C. in the reaction vessel 2 by the hot water supplied from the hot water conduit 15 to the jacket 14 as the first heat medium. Hold for a predetermined time. As a result, it is possible to obtain an ammonia-containing saccharification pretreatment product in which lignin is dissociated from the substrate or the substrate is swollen so that rice straw as the substrate can be enzymatically saccharified. In this embodiment, the said operation | movement corresponds to the process of obtaining an ammonia containing saccharification pre-processing thing.

  Next, in the pretreatment device 1, the ammonia contained in the ammonia-containing saccharification pretreatment product is diffused as a gas by opening the exhaust valve 9, and ammonia is condensed from the first exhaust conduit 8 through the bag filter 10. Guide to vessel 3. At this time, the pressure in the reaction vessel 2 is higher than the atmospheric pressure due to the heating, and by opening the exhaust valve 9, ammonia gas can be easily diffused from the ammonia-containing pre-saccharification product.

  The ammonia gas is cooled by low-temperature water supplied from the low-temperature water conduit 48 to the ammonia condenser 3 as a second heat medium, and a part of the ammonia gas is condensed and liquefied to form liquid ammonia. To the condensing tank 32. The liquid ammonia is further cooled by the low-temperature water supplied from the low-temperature water conduit 48 in the condensing tank 32 and then sent to the ammonia tank 5 via the first drainage pump 33.

  Further, the remaining part of the ammonia gas is introduced into the ammonia tank 5 through the second exhaust conduit 34 by opening the on-off valve 35. The pressure of the ammonia gas decreases as it is diffused, and when it becomes equal to atmospheric pressure, it becomes difficult to dissipate further. Therefore, in the pretreatment device 1, when the ammonia gas pressure becomes equal to the atmospheric pressure, the on-off valve 35 is closed and the vacuum pump 37 is operated to suck the ammonia in the reaction vessel 2, 2 is introduced into the ammonia tank 5 through the exhaust pipe 34 and the third exhaust pipe 36.

  In the reaction vessel 2, the ammonia-separated saccharification pretreatment product from which ammonia has been separated can be obtained as a result of the ammonia being diffused from the ammonia-containing saccharification pretreatment product as described above. In this embodiment, the said operation | movement corresponds to the process of obtaining the ammonia separation saccharification pre-processing thing.

  The ammonia separation saccharification pretreatment product is discharged from the discharge port (not shown) at the bottom of the reaction vessel 2 as described above and transferred to the next step. Then, the next process is prepared in the reaction vessel 2.

  On the other hand, the ammonia gas introduced into the ammonia tank 5 is then introduced into the ammonia absorption tower 4 communicating with the ammonia tank 5. In the ammonia absorption tower 4, the ammonia gas circulated by the circulation pump 40 via the ammonia water circulation conduit 38 is showered by the showering device 39, thereby absorbing (dissolving) the ammonia gas in the ammonia water.

  In this embodiment, the condensation of the ammonia gas in the ammonia condenser 3 and the absorption (dissolution) in the ammonia absorption tower 4 correspond to a process of recovering the diffused ammonia as ammonia water.

  At this time, an ammonia water heat exchanger 41 is provided in the middle of the ammonia water circulation conduit 38, and the heat of dissolution generated when the ammonia gas is absorbed (dissolved) in the ammonia water flows through the low temperature water conduit 48. Recovered with cold water. At the same time, the ammonia water is cooled.

  The ammonia water circulation conduit 38 is provided with an ammonia concentration sensor 42 for detecting the ammonia concentration of the ammonia water circulated through the ammonia water circulation conduit 38. When the ammonia concentration detected by the ammonia concentration sensor 42 becomes a predetermined value, for example, the concentration of the ammonia water supplied to the reaction vessel 2, the second water supply valve 44 is opened, and the second makeup water tank Pure water is supplied to the ammonia absorption tower 4 from 45 through the second supply water conduit 43. As a result, the concentration of ammonia water stored in the ammonia tank 5 can be maintained at a predetermined value, for example, the concentration of ammonia water supplied to the reaction vessel 2.

  The ammonia water stored in the ammonia tank 5 is cooled to a temperature in the range of 15 to 20 ° C., for example, as a result of condensation and cooling in the ammonia condenser 3 and the condensation tank 32 and dissolution in the ammonia water in the ammonia absorption tower 4. Has been. The ammonia water cooled to the temperature in the above range is taken out by the second drainage pump 47 through the second drainage conduit 46 and sent to an ammonia water tank (not shown) to prepare the substrate mixed solution in the reaction vessel 2. Reused.

  Next, the heating of the substrate mixture in the reaction vessel 2 will be described in more detail.

  In the pretreatment device 1, during the step of obtaining the substrate mixture, the first switching valve 20 is switched to connect the hot water conduit 15 and the hot water bypass conduit 21, and the hot water primary pump 17, the air cooling fan 18, and The binary heat pump 19 is activated. The hot water bypass conduit 21 is connected upstream and downstream by a second switching valve 22.

  In this way, the hot water stored in the hot water primary tank 16 is passed through the hot water conduit 15 through the hot water primary pump 17, the air cooling fan 18, the two-way heat pump 19, the first switching valve 20, and the hot water bypass conduit 21. Then, it is circulated through a path returning to the hot water primary tank 16. Here, the hot water is cooled by the air cooling fan 18 and then heated by exchanging heat with the heat medium of the binary heat pump 19 in the binary heat pump 19.

  The two-way heat pump 19 is a heat pump using two types of heat medium, and includes two types of heat medium circulation systems of a first circulation conduit 71 and a second circulation conduit 72 as shown in FIG. ing. As the two types of heat medium, for example, carbon dioxide is circulated through the first circulation conduit 71 and trifluoroethanol is circulated through the second circulation conduit 72.

  The first circulation conduit 71 is circulated to the expansion valve 73 and the first heat exchanger 74 that exchanges heat with the low-temperature water circulated to the low-temperature water conduit 48, the compressor 75, and the second circulation conduit 72. A second heat exchanger 76 that exchanges heat with fluoroethanol is provided. The second circulation conduit 72 is circulated to the expansion valve 77, the second heat exchanger 76 that exchanges heat with the carbon dioxide circulated to the first circulation conduit 71, the compressor 78, and the hot water conduit 15. A third heat exchanger 79 for exchanging heat with warm water is provided.

  At this time, the ammonia condenser 3 and the ammonia absorption tower 4 condense and absorb the ammonia generated in the previous process as described above, and the third switching valve 51 causes the upstream of the low-temperature water conduit 48 to be The low-temperature water primary pump 50 is operated while being connected to the downstream. As a result, the low temperature water stored in the low temperature water primary tank 49 is transferred to the low temperature water primary pump 50, the two-way heat pump 19, the third switching valve 51, the ammonia water heat exchanger 41, by the low temperature water conduit 48. It is circulated through a path returning to the low temperature water primary tank 49 via the condensation tank 32 and the ammonia condenser 3.

  Here, the low-temperature water is heated by exchanging heat with ammonia water in the ammonia water heat exchanger 41 and the condensation tank 32, and exchanging heat with ammonia gas in the ammonia condenser 3, and at the same time, the ammonia water and the ammonia water. Has been cooled. The low-temperature water is cooled to a temperature at which ammonia gas can be condensed in the ammonia condenser 3 by exchanging heat with carbon dioxide in the first heat exchanger 74 of the binary heat pump 19. The carbon dioxide is heated by exchanging heat with the low-temperature water in the first heat exchanger 74 of the binary heat pump 19.

  In the binary heat pump 19, the trifluoroethanol circulated through the second circulation conduit 72 exchanges heat with the carbon dioxide supplied through the first circulation conduit 71 in the second heat exchanger 76. Heated. The trifluoroethanol is cooled by exchanging heat with hot water supplied by the hot water conduit 15 in the third heat exchanger 79. As a result, the hot water supplied to the third heat exchanger 79 through the hot water conduit 15 is heated to a temperature at which the substrate mixture can be heated in the reaction vessel 2.

  In the pretreatment device 1, if the warm water circulated through the warm water conduit 15 is heated as described above, the warm water is not sufficiently heated immediately after the start of the binary heat pump 19. The hot water is heated to a temperature at which the substrate mixture can be heated in the reaction vessel 2. The hot water is passed from the hot water primary tank 16 through the hot water conduit 15, the hot water primary pump 17, the air cooling fan 18, the two-way heat pump 19, the first switching valve 20, and the hot water bypass conduit 21 as described above. The temperature is gradually raised by being circulated through the hot water primary tank 16.

  Therefore, in the pretreatment device 1, the first temperature sensor 23 is provided in the hot water conduit 15 on the secondary side of the binary heat pump 19 to detect the temperature of the hot water. The temperature of the hot water detected by the first temperature sensor 23 is higher than a predetermined value (for example, a temperature in the range of 80 to 85 ° C.) in which the substrate mixture is heated in the reaction vessel 2, for example, in a range of 90 to 95 ° C. Once heated to temperature, the second switching valve 22 is switched to connect the hot water bypass conduit 21 and the hot water conduit 24. As a result, hot water having a temperature in the above range (hereinafter referred to as high temperature water) is stored in the hot water secondary tank 25.

  The hot water is stored throughout the step of obtaining the substrate mixture. During this time, when the water level sensor (not shown) detects that the water level of the high temperature water stored in the hot water secondary tank 25 has reached the upper limit, the second switching valve 22 is connected to the upstream side of the hot water bypass conduit 21. The high-temperature water is circulated to the hot water primary tank 16.

  When the hot water stored in the hot water secondary tank 25 is insufficient, the first water supply valve 29 is opened, and the hot water 1 is supplied from the first make-up water tank 30 through the first make-up water conduit 28. The next tank 16 is supplied with pure water.

  Next, when the preparation of the substrate mixture is completed and the stage reaches the stage of heating the substrate mixture to a predetermined temperature, the hot water bypass conduit 21 and the hot water conduit 24 are connected by the second switching valve 22. Then, the hot water secondary pump 27 is operated. In this way, the high temperature water stored in the hot water secondary tank 25 is supplied to the jacket 14 of the reaction vessel 2 via the high temperature water supply conduit 26 and the hot water conduit 15, and the substrate mixture becomes the predetermined temperature. Heating up to reaching can be performed quickly.

  Next, if it is detected by a water level sensor (not shown) that the level of the high-temperature water stored in the hot water secondary tank 25 has reached the lower limit, the first switching valve 20 is set upstream of the hot water conduit 15. It is switched so as to connect the downstream. Then, the warm water led out from the upper part of the jacket 14 is passed through the warm water conduit 15 via the warm water primary tank 16, the warm water primary pump 17, the air cooling fan 18, the two-way heat pump 19, and the first switching valve 20. It shifts to a normal heating state that is circulated to the bottom.

  As a result, the substrate mixture is maintained at the predetermined temperature only by the heat energy supplied by the warm water in the normal heating state, and heating is continued.

  Next, cooling and condensation of ammonia gas by the ammonia condenser 3 will be described in more detail.

  In the pretreatment apparatus 1, during the step of obtaining the substrate mixture, the ammonia condenser 3 and the ammonia absorption tower 4 condense and absorb the ammonia generated in the previous treatment as described above. Therefore, the third switching valve 51 connects the upstream and downstream of the low-temperature water conduit 48, and the low-temperature water primary pump 50 is operated.

  As a result, the low temperature water stored in the low temperature water primary tank 49 is transferred to the low temperature water primary pump 50, the two-way heat pump 19, the third switching valve 51, the ammonia water heat exchanger 41, by the low temperature water conduit 48. It is circulated through a path returning to the low temperature water primary tank 49 via the condensation tank 32 and the ammonia condenser 3. Here, the low-temperature water is cooled by exchanging heat with the carbon dioxide in the first heat exchanger 74 of the binary heat pump 19.

  The carbon dioxide is cooled by exchanging heat with the trifluoroethanol in the second heat exchanger 76 of the binary heat pump 19. In addition, the trifluoroethanol is cooled by exchanging heat with the warm water circulating through the warm water conduit 15 and heating the substrate mixture in the third heat exchanger 79 of the binary heat pump 19. In other words, the low temperature water as the second heat medium is supplied to the binary heat pump 19 that heats the hot water as the first heat medium that heats the substrate mixture, whereby the binary system Cooling is performed by exchanging heat with the hot water as the first heat medium via the heat pump 19.

  According to the binary heat pump 19, the compression ratio of each of the two types of heat medium can be reduced, and the low temperature circulated through the low temperature water conduit 48 as compared with the case where a single heat medium is used. Water can be cooled efficiently.

  Therefore, the low-temperature water cools the ammonia water by exchanging heat with the ammonia water in the ammonia water heat exchanger 41 and the condensation tank 32, and cools the ammonia gas by exchanging heat with the ammonia gas in the ammonia condenser 3. To do. On the other hand, the low temperature water itself is heated by the ammonia water and the ammonia gas.

  During this time, when the water level of the high-temperature water stored in the hot water secondary tank 25 reaches the upper limit, the second switching valve 22 is switched so as to connect the upstream and downstream of the hot water bypass conduit 21 as described above. . In the pretreatment device 1, the third switching valve 51 is switched to connect the low temperature water conduit 48 and the low temperature water bypass conduit 52 in conjunction with the switching of the second switching valve 22. At this time, the low temperature water bypass conduit 52 is connected upstream and downstream by the fourth switching valve 53.

  In this way, the low temperature water stored in the low temperature water primary tank 49 is transferred to the low temperature water primary pump 50, the two-way heat pump 19, the third switching valve 51, and the low temperature water bypass conduit 52 by the low temperature water conduit 48. Through the fourth switching valve 53, the water is circulated through a path returning to the low temperature water primary tank 49. When the low-temperature water is circulated through the low-temperature water bypass conduit 52, the cooling of the ammonia water in the ammonia water heat exchanger 41 and the condensation tank 32 and the cooling of the ammonia gas in the ammonia condenser 3 are not performed. However, at this point, there is no problem because the emission of ammonia generated in the previous treatment is finished.

  At this time, the low-temperature water circulated through the low-temperature water conduit 48 exchanges heat with the carbon dioxide in the first heat exchanger 74 of the binary heat pump 19 as described above, whereby the ammonia in the ammonia condenser 3. It is cooled to a temperature at which the gas can be condensed, for example in the range of 10-15 ° C.

  In the pretreatment device 1, when the hot water circulated through the low temperature water conduit 48 is cooled as described above, the hot water is not sufficiently cooled immediately after the operation of the binary heat pump 19. At the same time, the low-temperature water is cooled to a temperature at which ammonia gas can be condensed by the ammonia condenser 3. Then, as described above, the low-temperature water is supplied from the low-temperature water primary tank 49 by the low-temperature water conduit 48 through the low-temperature water primary pump 50, the two-way heat pump 19, the third switching valve 51, and the low-temperature water bypass conduit 52. After being circulated to the low temperature water primary tank 49, it is gradually cooled to a lower temperature.

  Therefore, in the pretreatment device 1, the second temperature sensor 54 is provided in the low temperature water conduit 48 on the secondary side of the binary heat pump 19 to detect the temperature of the hot water. When the temperature of the low-temperature water detected by the second temperature sensor 54 is cooled to a temperature lower than the temperature at which the ammonia gas can be condensed by the ammonia condenser 3, the fourth switching valve 53 is connected to the low-temperature water bypass. It is switched to connect the conduit 52 and the cold water conduit 55. As a result, low temperature water (hereinafter referred to as cold water) cooled to a temperature lower than the temperature at which the ammonia gas can be condensed by the ammonia condenser 3 is stored in the low temperature water secondary tank 56.

  The storage of the cold water is performed after the third switching valve 51 is switched to connect the low-temperature water conduit 48 and the low-temperature water bypass conduit 52 during the step of obtaining the substrate mixture, and then the ammonia-containing saccharification pretreatment product Is performed throughout the process of obtaining During this time, when the water level sensor (not shown) detects that the water level of the cold water stored in the low temperature water secondary tank 56 has reached the upper limit, the fourth switching valve 53 is located upstream of the low temperature water bypass conduit 52. Are switched to connect the downstream and the downstream, and the cold water is circulated to the low temperature water primary tank 49.

  When the cold water stored in the low temperature water secondary tank 56 is insufficient, the third water supply valve 60 is opened, and the low temperature water is supplied from the third makeup water tank 61 through the third makeup water conduit 59. Pure water is supplied to the primary tank 49.

  Next, the ammonia-containing saccharification pretreatment product is obtained in the reaction vessel 2, the exhaust valve 9 is opened, and the ammonia gas released from the ammonia-containing saccharification pretreatment product is introduced into the ammonia condenser 3. If it arrives, the low temperature water secondary pump 58 is operated in the state where the low temperature water bypass conduit 52 and the cold water conduit 55 are connected by the fourth switching valve 53. In this way, the cold water stored in the low-temperature water secondary tank 56 passes through the cold water supply conduit 57 and the low-temperature water conduit 48, passes through the ammonia water heat exchanger 41 and the condensation tank 32, and then enters the ammonia condenser 3. To be supplied.

  Since the pretreatment method of the present embodiment is a batch type, when the ammonia gas is condensed in the ammonia condenser 3, a high concentration and a large amount of ammonia gas is condensed in the initial stage of the ammonia gas emission. Introduced into the vessel 3. For this reason, in the initial stage, a large amount of cooling heat energy is required to quickly cool the ammonia gas. However, according to the pretreatment device 1 of the present embodiment, the cold water stored in the low-temperature water secondary tank 56 is supplied to the ammonia condenser 3 so that the high-concentration and a large amount of ammonia gas can be efficiently and quickly supplied. It can be cooled and fully condensed.

  At this time, by setting the flow rate of the low-temperature water secondary pump 58 to be larger than the flow rate of the low-temperature water primary pump 50, the ammonia condenser 3 is more effective than the case where low-temperature water is circulated using only the normal low-temperature water conduit 48. Since the quantity of the cold water supplied to can be enlarged, it is preferable.

  The cold water supplied to the ammonia condenser 3 is used for cooling the ammonia gas and then discharged through a low-temperature water conduit 48. Then, after being supplied from the low temperature water primary pump 50 to the binary heat pump 19 and recooled, it is returned to the low temperature water secondary tank 56 via the low temperature water bypass conduit 52 and the cold water conduit 55.

  However, since the flow rate of the low-temperature water secondary pump 58 is larger than the flow rate of the low-temperature water primary pump 50, the amount of cold water stored in the low-temperature water secondary tank 56 gradually decreases. Therefore, if the water level sensor (not shown) detects that the water level of the cold water stored in the low temperature water secondary tank 56 has reached the lower limit, the third switching valve 51 is connected to the upstream side of the low temperature water conduit 48. It is switched so as to connect the downstream.

  Then, the low temperature water derived from the ammonia condenser 3 is supplied to the low temperature water primary tank 49, the low temperature water primary pump 50, the two-way heat pump 19, the third switching valve 51, the ammonia water heat exchanger through the low temperature water conduit 48. 41. The state is changed to a normal cooling state circulated to the ammonia condenser 3 through the condensation tank 32. At this time, since the concentration and amount of the ammonia gas to be diffused have already been reduced, the ammonia gas can be sufficiently cooled and condensed by the low-temperature water in the normal cooling state.

  DESCRIPTION OF SYMBOLS 1 ... Pretreatment apparatus, 2 ... Reaction container, 3 ... Ammonia condenser, 4 ... Ammonia absorption tower, 5 ... Ammonia tank, 15 ... Hot water conduit, 16 ... Hot water primary tank, 19 ... Two-way heat pump, 21 ... Hot water Bypass conduit, 24 ... Hot water conduit, 25 ... Hot water secondary tank, 26 ... Hot water supply conduit, 48 ... Low temperature water conduit, 49 ... Low temperature water primary tank.

Claims (3)

A step of mixing a lignocellulosic biomass as a substrate with ammonia water in a batch system to obtain a substrate mixture, and heating the substrate mixture to a predetermined temperature and holding the substrate mixture at the temperature for a predetermined time, thereby lignin from the substrate. Dissociating or swelling the substrate to obtain an ammonia-containing saccharification pretreatment product, and releasing ammonia from the ammonia-containing saccharification pretreatment product to obtain an ammonia separation saccharification pretreatment product from which ammonia has been separated, and A step of cooling and condensing ammonia released from the ammonia-containing saccharification pretreatment product and dissolving it in water to recover it as ammonia water,
The second heat medium is supplied to a heat pump that heats the first heat medium that heats the substrate mixture, and the second heat medium is cooled by exchanging heat with the first heat medium. In the biomass pretreatment method of cooling the ammonia by using the second heat medium thus produced,
A circulation path for circulating the second heat medium to the heat pump and the part for cooling the ammonia is provided with a bypass circulation path for avoiding the part for cooling the ammonia and circulating to the heat pump. By circulating in the bypass circulation path, the second heat medium is cooled to a temperature lower than the temperature when circulating the second heat medium to the circulation path, and is cooled to a temperature lower than the temperature when circulating to the circulation path. A predetermined amount of the heat medium is stored in advance, and the concentration of the released ammonia is reduced to a predetermined concentration from the initial stage of ammonia emission of the ammonia-containing saccharification pretreatment product , and the amount of the ammonia is reduced. A biomass pretreatment method, wherein the ammonia is cooled by the stored second heat medium until the amount is reduced to a predetermined amount.   The biomass pretreatment method according to claim 1, wherein the heat pump is a binary heat pump.   The biomass pretreatment method according to claim 1 or 2, wherein the storage of the second heat medium is performed between the step of obtaining the substrate mixture and the step of obtaining the ammonia-containing saccharification pretreatment product. A biomass pretreatment method characterized.

Images